Selector switch



Jan. 3, 1928.

.H. W-. GOF F SELECTOR SWITCH 7 Filed April 30 1926 Harold w Gbff an). I

Patented Jan. 3, 1928.

UNITED STATES 1555,0545 PATENT QFFl-CE.

HAROLD W. eornorennar NECK, NEV] YORKQ'ASSIGNOR TO. BELL TELEPHONE LABO- R'ATORIES, INCORPORATED, F NEVF YORK, N. Y., A CORPORATION OF NEVI YORK;

SELECTOR SWITCH.

Application filed April 30, 1926. Serial No. 105,670.

certain terminals of the bank form a second.

part of the switch for interconnecting lines. A well known method of el'ev'at'ii'ig brushes to a desired terminal connection is shown in Patent No. 1,123,696 to E. B. Craft, et al, granted January 5, 1915. The brushes are permanently fastened to a drive shaft which is driven up or down by friction rolls when placed thereagainst by rolls on the armatures of magnets. The energization and deenergization of the magnets is controlled to position the. brushes upon the desired terminals.

In the methods hereinbefore employed, a difliculty is encountered in centering the brushes upon the terminals, since there is a variation in the time of releasing the drive shaft. To care for this variation it has been customary to allow overthrow of the drive shaft and brushes after the release of the magnet. When the thrust of the overthrow has been expended, the drive shaft andbrushes move downward by force of gravity and the brushes are centered upon the, terminals by the use of a rack fastened to the drive shaft. Very rapidly operating apparatus is required to control the drive shaft magnets, and this apparatus must be maintained in careful adjustment in order that the brushes do not overthrow to a set of terminals above the ones to which they are directed. For this reason, it is desirable to eliminate the necessityfor overthrow by the use of a brush driving combination which may be quickly released.

It is the principal object of the present invention to improve the brush-driving mechanism for automatic switches.

The present invention contemplates use of a magnet permanently attached to a drive shaft, an armature attached to brushes by a flexible union, means'operated on the energization of the magnet to attract the armature for moving the brushes in either directive movement of the drive shaft, and means effective on the de-energization of the magnet to release the armature and arrest the movement of the brushes for associating them with the desired set of terminals independent of overthrow of said brushes or; for returning said? brushes to their normal position. To facilitate the movement of the brushes, cams are attached to the armature pole piece for holding the brush springs away from the terminals as the brushes are movedupward.

A switch embodying the above enumerated features may be driven in essentially the same manner as that now used in panel type switches and which is disclosed in the above mentioned patent to E. B. Craft et al. The circuit arrangement for controlling the drive shaft and the magnet fastened thereto is disclosed in patent to N, G. Blauvelt, No. 1,634,734, granted July 5, 1927,. For a clearer understanding of the above features reference may be made to the accompanying drawings, in which:

Fig. 1 is side view partially in section of a switch structure; Fig. 2 is a view of the brush carriage in position on a terminal rack, facing thebank; Fig. 3 is a view of the brush carr age from the side opposite that shown in Fig. 1; Fig. 4, shows the relative. position of the. magnet and armature with, the magnet de-energized' and energized; Fig. 5 shows a. partial" cutraway sidev view of the magnet and armature with the magnet oper- U ated; Fig. 6 shows a, view of the brushes while being, driven upward F ig. 7 shows a view looking down on the brushes andv terminal strips; and Fig. 8 shows a cross-section of the terminal bank.

As above indicated the drive rod 1 may be of the, type commonly employed in panel type switches. The rod 1 is driven upwardby means of roll 3 which is brought into frictional engagement with strip 4 by magnet 5. Similarly magnet 6 brings rack 1 into contact with roll 2 to restore the drive rod. No trip magnet and no latch are necessary since the brush set is, selected directly and the drive rod remains stationary only in its normal position. A commutator 7 is pro.- vided for controlling selections as in other paneltype switches, although the segments would be arranged to cooperate with the appropriate control circuit. The brush rod is also adapted to close certain contacts (not shown) which form portions of the control circuit.

Magnets 8, 9, etc. are fixed to the drive rod and current is supplied thereto in any desired manner. Each magnet, such as magnet 8, is provided with a U-shaped polepiece 10 which extends beyond the magnet winding and mounting. A magnet is provided for each panel making up the bank and a panel is selected by energizing the corresponding magnet.

The brush carriage consists of a frame 11 on which the remaining apparatus is mounted. The frame 11 slides on guide rod 12 and is held in place by the frictional engagement of shoes 13, 14, 15 and 16 with 'the' rod 12. Shoes 14 and-16 are fixed to frame 11 at one side of rod 12, and shoes 13 and 15 are fixed to a spring proje tion 17 on frame 11 which brings these shoesinto resilient engagement with the opposite side of the guide rod. The shoes 13' and 141 are pivotally connected at one side as are shoes 15 and 16. These shoes havea cylindrical inner surface thus providing a relatively large contacting surface The arrangement of the brushes, together with the shape and arrangement of these shoes provide for the ready attachment of brush sets to rod 12 and the easy substitution of a fresh set for one which becomes defective. The shoes are held in place by pins, and may also be renewed readily.

In order to reduce the pressure of the shoes 13 to 16 on the rod 12 and to facilitate the movement and centering of the brushes 18, 19 and 20, rollers 42' are resiliently mounted on the frame 11. These rollers soon as the power is removed they hold the brush set in place.

The brushes 18, '19 and 20 are mounted vertically and areinsulated from the frame 11 by blocks of insulation 21. Side by side with each brush and in electrical connection therewith are feed brushes 22, 23 and 24. The terminal lugs 25 of the panel bank are arranged in vertical rows, and along one side of each row is a conducting strip 26 insulated from the rows of terminals. These strips afford convenient means for connectingthe control circuit with the brush set. The feed brushes are consta-ntlyin engagement with the feed strips, but in order to prevent intereference with busy outgoing lines or injury to the brushes themselves, the

tip and ring brushes are lifted from their terminals during hunting. This is accomplished by the use of a pair of camming rolls 27 and.28. These rolls are carried by the same lever arm 30 as is the armature 29 and when this arm is raised by the upward pull 'of the drive magnet the camming rolls 27 The armature 29 is mounted on the arm 30' of magnetic material. This arm is supported on frame 11by a shdable hinge arrangement. PIOJe'fiLlOIl 31' normally rests on horizontal portion 32 of frame 11 forming a knife edge fulcrum for. the arm 30 to swing on. The vertical strips 3 1 and 33 en- The sleeve brush 19 has a camming gage slots in portion 32 and permit vertical motion of the arm 30. Spring 35 connects a projection 36 on frame 11 with a projection 37' on arm 30, in. such a way as to tend to hold the arm 30 in the position shown in Fig. 3. Extensions 39 on the arm 30 are bent at right angles to the arm forming a secondary armature. The arm 41 serves to control certain normal contacts (not shown).

Magnet 8 and the brush set normally oc cupy the relative positions shown in Fig. 1. When magnet 8 is energized, the armature 29 is drawn toward the magnet and under the polepiece 10 as shown in Figs. 4. and 5. When, now, the updr'ive magnet 5 is energized and magnet 8 is moved upward, the arm 30 is first moved upward to withdraw brushes 18 and 20 from their terminals and then the brush set is moved with the magnet. \Vhen the desired outgoing line has been found, the magnet 8 is tie-energized. The spring 35 qulckly withdraws the armature and the brush set is held'in position by the engagement of the cams 12 with the terminal strips. The restoration of the armature permits brushes 18 to 20 to make contact with terminals and complete the connection. As set forth in the above identified Blauvelt patent, the brush rod continues to move, upward until a top contact closed by the drive rod opens the circuit of the updrive magnet'5 and closes that'of downdrive magnet 6. Magnet .8 being de-energized during the downward movement, the brush set is unaffected.

\Vhen'the brush set is to be restored, the

magnet is carried to the top of'the panel and is there energized. As the energized magnet comes opposite the brush set, it exerts a force on the extensions 39 or secondary armature drawing the armature 29 forward and into position to be more readily engaged by the magnet. Since the polepieces of the magnet exert a strong physical pressure on the armature 29 on the downward movement and might therefore prevent the retraction of the armature when the magnet 8 is deenergized or its complete attraction when the magnet is re-energized, a spring i0 is provided to give the drive rod a slight upward displacement at the end. of its down stroke to free the armature and to permit its complete attraction when the magnet is subsequently energized.

lVhat is claimed is:

1. In an automatic switch, a terminal bank, a movable brush set, a movable shaft and a magnet secured thereto, and means under the control of said magnet to move said brush set into position with respect to said terminal bank and to restore it to its normal position.

2. In an automatic switch, a terminal bank, a movable brush set, a movable driving shaft, an electro-magnet secured to said driving shaft, and means effective on the operation of said magnet for moving said brushes with the directive movement of said driving shaft comprising an armature for said magnet flexibly attached to said brush set.

3. In an automatic switch, a terminal bank, a movable brush set, amovable driving shaft, an electro-magnet secured to said driving shaft, means effective on the operation of said magnet for moving said brushes with the directive movement of said driving shaft comprising an armature for said magnet flexibly attached to said brush set, and means effective upon the release of said magnet to arrest the movement of said brush set.

4:. In an automatic switch, a terminal bank, a movable brush set, a movable shaft and an electro-magnet secured thereto, means under the control of said magnet to move said brush set into position with respect to said terminal bank and to restore it to its normal position, and resiliently mounted means on said brush set to hold said brush set in position with respect to said terminal bank.

5. In an automatic switch, a terminal bank, a movable brush set, a movable driving shaft, an electro-magnet secured to said driving shaft, means effective on the operation of said magnet for moving said brushes with either directive movement of said driving shaft, comprising an armature for said magnet fleX- ibly attached to said brush set, and resiliently mounted means on said brush set to hold said brush set in position with respect to said terminal bank.

6. In an automatic switch, a terminal bank,

shaft, means effective on the operation of said magnet for moving said brushes with either directive movement of said driving shaft comprising an armature for said mag net flexibly attached to said brush set, and resiliently mounted means on said brush set effective'upon the release of said magnet to hold said brush set in position with respect to said terminal bank.

7. In an automatic switch, a terminal bank, a movable brush set, a movable driving shaft, an electro-magnet secured to said driving shaft, means effective on the operation of said magnet for moving said brushes with either directive movement of said driving shaft comprising an armature for said magnet flexibly attached to said brush set, and resiliently mounted rollers on said brush set effective upon the release of said magnet to hold said brush set in position with respect to sa'd terminal bank.

8. In an automatic switch, a terminal bank, a movable brush set, a movable driving shaft, an electro-n gnet secured to said driving shaft, means effective on the operation of said magnet for moving said brushes with the directive movement of said driving shaft comprising an armature for said magnet flexibly attached to said brush set, and means for holding the talking circuit brushes away from their terminals as the brush set is moved upward.

9. In an automatic switch, a terminal bank, a movable brush set, a movable driving shaft, a magnet secured to said driving shaft, means effective on the operation of said magnet for moving said brushes with the movement of said driving shaft comprising an armature for said magnet flexibly attached to said brush set, and means operated by said armature for holding the talking circuit brushes away from their terminals as the brush set is moved upward.

10. In an automatic switch, a terminal bank, a movable brush set, a movable driving shaft, an electro-magnet secured to said driving shaft, means effective on the operation of said magnet for moving said brushes with either directive movementof said driving shaft comprising an armature for said magnet flexibly attached to said brush set, and cams controlled by said armature for holding the talking circuit brushes away from their terminals as the brush set is moved upward.

In witness whereof, I hereunto subscribe my name this 29th day of April, A. 1)., 1926.

HAROLD IV. GOFF. 

